Polycyclic aromatic hydrocarbon growth in a benzene discharge explored by IR-UV action spectroscopy

Abstract

IR-UV spectroscopy of a benzene discharge reveals larger PAHs and intermediates showing that different gas-phase PAH growth mechanisms can occur under the same conditions. The identifications are promising candidates for radio astronomy searches.

Formation of the acenaphthylene cation as a common C2H2-loss fragment in dissociative ionization of the PAH isomers anthracene and phenanthrene

“…55 and o-benzyne has been shown to lead to the formation of cyclopentadiene (C 5 H 6 ) and indene, respectively, as the primary isomer products, 57,58 and a variety of five-membered ring structures were spectroscopically detected in benzene and naphthalene discharges. [59][60][61] We also note that in the AcN + and BP + spectra the bands around 1000 to 1150 cm À1 (8.7-10 mm) correspond to the in-plane C-H bending vibration involving the pentagonal ring. Features in this range were also observed in the IR spectra of rubicene + , 62 corannulene + , 63 and diindenoperylene + 64 and were found to involve the pentagonal structures.…”

“…The reaction of neutral allyl radicals (C 3 H 5 ˙) with acetylene (C 2 H 2 ) and o -benzyne has been shown to lead to the formation of cyclopentadiene (C 5 H 6 ) and indene, respectively, as the primary isomer products, 57,58 and a variety of five-membered ring structures were spectroscopically detected in benzene and naphthalene discharges. 59–61…”

Low Energy Isomers and Infrared Spectra Simulations of C4H3N, C4H4N, and C4H5N and Related Ions

“…Therefore, the simulations of infrared (IR) spectra are imperative for band assignment of molecules detected in isolated matrices or ion traps for their unique identification. − The vibrational spectra of C 4 H 3 N and C 4 H 5 N systems at neutral states were investigated under different experimental conditions. − Also, infrared spectra simulations of the low-lying energy structures of similar systems were performed. ,, The IR analysis combined with mass spectra can be used as good indicators of the presence of specific isomers in the experimental data …”

“…44,53,54 The IR analysis combined with mass spectra can be used as good indicators of the presence of specific isomers in the experimental data. 55 As shown, several works were already dedicated to pyrrole (C 4 H 5 N) and its low-energy isomers 56−59 and its derivatives C 4 H 4 N, 31,54 C 4 H 3 N, 25,47,53 and C 4 H 2 N. 24 Despite the available computational studies on these species, a systematic search for a global minimum (GM) and low-lying energy isomers of C 4 H n N (n = 3−5) and related charged species was not performed. In this way, we conducted a global minimum optimization based on a genetic algorithm on neutral, anionic, and cationic charge states.…”

Evaluated electron scattering cross section dataset for gaseous benzene in the energy range 0.1–1000 eV

“…From a technological perspective, this chemical compound holds significant importance in petroleum industries 1 playing a crucial role in various fundamental processes, such as its involvement in alkylation with ethylene to produce ethylbenzene, which serves as the primary feedstock for the production of styrene monomers. 2 In addition, benzene has attracted the attention of the astrochemistry research community, 3,4 both because of the difficulty in finding its means of formation 5,6 and because of its role as a building block for polycyclic aromatic hydrocarbons (PAHs), 7 which have been identified in the interstellar medium 8,9 and are considered to play a fundamental role in carbon astrochemistry. 10 As a consequence electron interactions with gaseous benzene have been extensively studied with both experimental [11][12][13][14][15][16][17][18][19] and theoretical 14,[20][21][22][23][24][25][26] methods (see also references therein).…”